April 3, 2006 - Monday - The
first stop on our full day
tour of Florence today was the Science
History Museum, where we saw Galileo's original telescopes, among many other old
scientific instruments originally collected by the Medici and Lorraine
families. We had a very nice
Canadian-born young woman as a guide to several of the exhibits. She
demonstrated how some of the exhibits were used for research and entertainment.
Keep in mind, science in the era when these instruments were made and used was
sponsored by rich families. Scientists of the day wouldn't have patrons to
support their work unless they kept them engaged, which often meant they had to
invent entertaining instruments that could be given to their patrons and
their families to play with. For example, the museum has a huge collection
of static electricity machines. There is little scientific value in them,
but they made for very entertaining parlor games!

The Science
History Museum has a superb website, and most
of it is available in English, so please browse it when you have some spare time
to explore. The following
descriptive text and photos are copyright the Science History Museum, Florence.

"The first evidence of Galileo's espousal of
heliocentrism came in a letter to Kepler of 1597, in which he described himself
as a long-standing Copernican. His astronomical discoveries of 1610, achieved
thanks to the telescope, thus came as a confirmation of earlier-held beliefs.
With the Sidereus Nuncius, Galileo inaugurated modern cosmology. He showed that
the Moon had Earth-like valleys and mountains; that the Milky Way is not a
denser part of the heavens, but an impressive array of stars; and that Jupiter
is surrounded by four satellites. These discoveries destroyed the very
foundations of Aristotelian-Ptolemaic cosmology. Later, Galileo made other
extraordinary observations that bolstered his Copernican faith: the strange
appearances of Saturn, the phases of Venus, and sunspots."

This telescope, attributed to Galileo, comprises a main tube and two smaller
housings in which the objective and the eyepiece are mounted. The main tube
consists of two semicircular tubes held together with copper wire. It is
covered with paper. The objective measures 51 mm in diameter, and is
biconvex, but the radii of curvature of the surfaces of the two faces are
not equal; the focal length is 1,330 mm, the thickness at the center 2.5 mm.
The eyepiece is plano-concave and measures 26 mm in diameter; the concave
side, facing the eye, has a radius of curvature of 48.5 mm; the thickness at
the center is 3.0 mm, the focal length -94 mm (the negative focal length
means that the lens is diverging). The instrument's magnification is 14 and
its field of view 15'. The attribution to Galileo is due to the fact that
some of its elements—in particular, the characteristic concave eyepiece—are
typical of the telescopes that he produced in great numbers between 1610 and
1640. In 1611, Prince Federico Cesi, founder of the Accademia dei Lincei,
suggested calling this instrument telescopio [from the Greek tele ("far")
and scopeo ("I see")]. Science History Museum, Florence

Galileo designed ingenious accessories for the telescope's various
applications. One of the most important was the micrometer, an indispensable
device for measuring distances between Jupiter and its moons. Another was
the helioscope, which made it possible to observe sunspots through the
telescope without risking eye damage. Science History Museum, Florence

Newtonian telescope. Reflecting
telescope of the Newtonian type with an octagonal wooden tube blackened
internally. The telescope can perform altitude and azimuth movements by
means of metal arcs. The wooden stand has four legs with castors. The
focusing mirror, the secondary 45-degree mirror, the eyepiece and the finder
are missing. Science History Museum, Florence

Objective lens used by Galileo for many observations in 1609-1610. In
1610, he was the first to observe Jupiter's moons, which he called the "Medicean
Planets." He announced his great discovery in Sidereus Nuncius [The Starry
Messenger], published in Venice the same year. Galileo donated the lens of
the telescope with which he made the discovery to Grand Duke Ferdinand II.
At a later date, the lens was accidentally cracked. Science History Museum,
Florence

A close-up of the objective
lens used by Galileo Science History Museum, Florence

The Sidereus Nuncius is the work in which Galileo announced the
discovery of Jupiter's moons. Using drawings and illustrations, he analyzed
the new celestial phenomena observed with the telescope in Padua in early
1610. The work initiated a process that would lead, in a few decades, to the
acceptance of the Copernican system despite opposition from ecclesiastical
authorities. The work's publication and its dedication to the Medici of
Jupiter's moons (which Galileo named the "Medicean Stars") opened the path
for the return of Galileo to Tuscany, Cosimo II having appointed him
Granducal Mathematician and Philosopher. A few months after the Sidereus
Nuncius appeared, the Pisan scientist observed "three-bodied Saturn,"
sunspots, and the phases of Venus, which provided further evidence against
the Aristotelian-Ptolemaic system. Science History Museum, Florence

Middle finger of Galileo's right hand.
This item exemplifies the celebration of Galileo as a hero and martyr of
science. The finger was detached from the body by Anton Francesco Gori on
March 12, 1737. Science History Museum, Florence

Galileo Galilei Science History Museum, Florence

Galileo and Viviani.
Tito Lessi's painting shows Galileo in old age with Vincenzo Viviani. After
his condemnation in 1633, Galileo was confined to the villa Il Gioiello in
Arcetri, where Viviani assisted him from 1639 until his death in 1642.
Science History Museum, Florence